(a) Field of the Invention
The present invention relates to a method and apparatus for allocating dynamic bandwidth. More particularly, the present invention relates to a method and apparatus for allocating dynamic bandwidth that can allocate bandwidth in consideration of queue size information of an optical network unit.
(b) Description of the Related Art
Optical access network technology is technology for effectively providing a necessary bandwidth for subscribers in the first mile, and usually has a point-to-point or a point-to-multipoint structure. In general, a point-to-point structure is used for an active optical network and a point-to-multipoint structure is mainly used for a passive optical network, and they are standardized in international standard organizations such as the Institute of Electrical and Electronics Engineers (IEEE) and the International Telecommunication Union Telecommunication Standardization Sector (ITU-T).
A passive optical network (PON) has a tree structure in which an optical line terminal (OLT) of a telephone office corresponds at 1-to-N to a plurality of optical network units (ONU) through a passive element.
In downward transmission in such a PON, because data transmitting from the OLT are broadcasted in all ONUs, a problem of medium sharing does not occur. However, because a plurality of ONUs are connected to an OLT through one optical fiber, in order to perform upward transmission without collision between ONUs, a time division multiple access medium access control (TDMA MAC) protocol for accessing a medium while avoiding overlapping of time is required.
Particularly, in a gigabit passive optical network (hereinafter referred to as a “GPON”) standard that is set at the ITU-T, in order to receive traffic of various characteristics, each ONU has a class queue (hereinafter referred to as a “T-CONT queue”) of a separate transmission container (T-CONT) on a service class basis and stores and transmits upward data on a priority order basis.
When a service level agreement (SLA) parameter for a class queue is set in such an ONU, a T-CONT queue of the ONU should store packets that are input for a predetermined allocation cycle. When the size of the T-CONT queue is insufficient to store packets that are input for an allocation cycle, packet drop occurs.
Therefore, when an SLA parameter is set in the OLT, technology for allocating a bandwidth in consideration of a buffer size of a T-CONT queue of each ONU is requested.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.